Binder Compositions and Uses Thereof

ABSTRACT

The present invention relates to a new aqueous curable binder composition comprising a polyphenolic macromolecular compound which bears a multitude of catechol radicals (dihydroxybenzene), preferably lignosulfonate salts and condensed tannins and mixtures thereof, and a polyamine functional compound comprising primary and/or secondary and/or tertiary and/or quaternary amine functional groups, suitable for bonding particulate matter, such as fibers, more particularly mineral wool fibers, or particles, such as wood particles.

The present invention relates to binder compositions, more specificallycurable binder compositions for use in manufacturing products from acollection of non or loosely assembled matter. For example, these bindercompositions may be employed to fabricate fiber products which may bemade from woven or nonwoven fibers. In one illustrative embodiment, thebinder compositions are used to bind glass fibers to make fiberglass. Inanother illustrative embodiment, the binder compositions are used tobind mineral wool fibers, such as glass wool or stone wool in a mattedlayer, such as an insulating product. In a further embodiment, thebinders are used to make cellulosic compositions. With respect tocellulosic compositions, the binders may be used to bind cellulosicmatter to fabricate, for example, wood fiber board or particle boardwhich has desirable physical properties (e.g., mechanical strength). Theinvention further extends to a product made from loosely assembledmatter bound by a binder of the invention.

Known thermosetting binders comprise a variety of phenol-aldehyde,urea-aldehyde, melamine-aldehyde, and other condensation-polymerizationmaterials such as furane and polyurethane resins. Aldehyde based bindersand more particularly formaldehyde based or generating binders arewidely used.

Alternative formaldehyde-free binder compositions includepolyester-based binders obtained by the reaction of a polycarboxylicacid polymer and a polyol that form a thermoset when heat cured. Morerecently, formaldehyde free binders have been made from sustainablematerials, such as from the condensation of amine groups containingcompounds with reducing sugars as thermosets. These alternativechemistries show advantages as compared to prior formaldehyde basedtechnology, but also show certain weaknesses, and there is still a needfor alternative binder chemistry. Some of these known binder chemistriesshow a relatively high loss of water in the condensation reaction, whichmay have a negative impact on the internal bond strength and/or swellingproperties of products.

A. Faure et al disclose in their review article “Catechols as versatileplatforms in polymer chemistry” published in Progress in Polymer Science38 (2013), 236-270, that catechol units containing compounds show strongadhesion to a large range of surfaces, even under wet conditions. Theauthors review methods to incorporate catechol units in complexfunctionalized macromolecules.

The present invention seeks to provide binders which generate or promotecohesion and are capable of holding a collection of matter together suchthat the matter adheres in a manner to resist separation. An objectiveof the present invention is to provide binders showing high bondstrength.

Another objective of the present invention is to provide cost-effectivebinder compositions for large volume applications.

Another objective is to provide a binder composition based on renewableand/or sustainable resources.

Further, the invention seeks to provide binder compositions that rapidlycure into strong binders.

Yet another purpose of the invention is to provide an assembly of matterbonded with the invention binder.

Lignin is a constituent of woody plants, composed of a complex group ofphenolic polymers that provide strength and rigidity to woody cell wallsof various plants. The lignin molecule is complex and not yet fullyunderstood. Lignosulfonates are derived from lignin by sulfonation, forinstance in a wood pulping process, more specifically with salts ofbisulfite/sulfite. The sulfonate complex may be in association withcalcium, magnesium, ammonium, or sodium. Lignin and its derivatives haveseveral advantages, such as renewability, biodegradability, low cost andavailable supply. Lignosulfonates are used in the concrete industry asdispersing agents and to delay the setting of concrete. They may be usedas additives in oil well drilling, dispersants for dyestuffs, cleaningagents, and as a partial substitute for phenol in the manufacture ofadhesives. Sodium lignosulfonate is potentially useful in inhibitingcorrosion and scale formation in recirculating cooling water systems. Insome applications, lignosulfonate salts are reacted with certain aminesto form dyes (see for instance U.S. Pat. No. 5,989,299) or dispersants.U.S. Pat. No. 4,130,515 discloses a lignin-based resin binder producedby copolymerization of a lignosulfonate salt with melamine andformaldehyde.

The present invention now provides an aqueous curable binder compositioncomprising a polyphenolic macromolecular compound and a polyaminefunctional compound and/or a reaction product thereof, in accordancewith the claims. The term polyphenolic macromolecular compound as usedherein designates a macromolecular compound, preferably an essentiallynatural macromolecular compound or a macromolecular compound derivedfrom a natural macromolecular compound, which bears a multitude ofphenol or polyhydroxybenzene radicals, such as catechol radicals(dihydroxybenzene). Examples of such polyphenolic macromolecularcompounds are lignosulfonate salts and condensed tannins and mixturesthereof.

Lignosulfonate salts may advantageously be selected from calciumlignosulfonate, sodium lignosulfonate, ammonium lignosulfonate,magnesium lignosulfonate and mixtures thereof.

Tannins are commonly found in plants. Compounds of interest inaccordance with the invention comprise polyphenolic macromolecularcompounds, hence may be essentially condensed tannins.

According to the present invention, the polyamine functional compoundcomprises primary and/or secondary and/or tertiary and/or quaternaryamine functional groups and may be selected from diamines, triamines,tetramines, pentamines and polymeric plolyamines or polyimines. Examplesare hexamethylenediamine, diethylenetetramine, diethylenetriamine,polyethyleneimine (PEI), polyvinyl amine, polyether amine, polylysine,ethylene diamine, 1,3-diaminopropane, cadaverine, spermidine, spermine,putrescine, tetraethylmethylenediamine, and triethylenetetramine. As isknown to the skilled person, several different types ofpolyethylenimines are available, such as linear polyethylenimines,branched polyethylenimines and dendrimer type polyethylenimine.Similarly, polyetheramines may show a linear form and branched forms,and all are believed to be suitable for the generation of bindercompositions and, hence, binders of the invention.

The ratio of polyphenolic macromolecular compound to polyaminefunctional compound ranges from 98:2 to 70:30 w %, preferably from 95:5to 80:20 w %.

Preferably, the ratio of reactive groups on the macromelules to reactiveamino groups in the amine components may be in the range of 10:1 to 1:1.

Preferred binder compositions comprise a lignosulfonate salt, preferablyammonium lignosulfonate or calcium or magnesium lignosulfonate, and adiamine, such as hexamethylenediamine (HMDA).

Preferably such binder compositions further comprise a matrix polymer,such as polymers of natural and/or synthetic origin. These polymers mayact as an active filling agent in the binder formulation, and may formintra- and inter-molecular chain interactions. Naturally derivedpolymers may advantageously be selected from cellulose and itsderivatives, such as cellulose ether and ester derivatives. Thecellulose ether derivatives can be prepared by carboxymethylation,carboxyethylation and carboxypropylation. Examples of preferredcellulose ether derivatives are: carboxymethyl cellulose (CMC), sodiumcarboxymethyl cellulose (NaCMC), hydroxypropyl cellulose (HPC),hydroxyethyl cellulose (HEC), hydroxypropylmethyl cellulose (HPMC),methyl cellulose (MC), ethyl cellulose (EC), trityl cellulose, and soon. The cellulose ester derivatives can be prepared by esterification ofcellulose. The ester derivatives include acetates, butyrates, benzoates,phthalates and anthranilic acid esters of cellulose, preferably,cellulose acetate phthalate (CAP), cellulose acetate butyrate (CAB),cellulose acetate trimelitate (CAT), hydroxylpropylmethyl cellulosephthalate (HPMCP), succinoyl cellulose, cellulose fuoroate, cellulosecarbanilate, and mixture thereof. In some binder compositions cationiccellulose derivatives may be used. Some binder compositions may compriseother polysaccharides such as alginates, starch, chitin and chitosan,agarose, hyaluronic acid, and their derivatives or copolymers (e.g.,graft-copolymer, block copolymer, random copolymers), or mixturesthereof.

Synthetically derived polymers may include polyacrylates,polymethacrylates, polyacrylamides, polymethacrylamides, polyurethanes,polyesters, polyvinyls and/or their copolymers, and aliphatic isocyanateoligomers, compounds containing one or more azetidinium group, ormixtures thereof.

In one embodiment the binder formulation may comprise polyacrylate,polymethacrylate or polyacrylamide or mixtures thereof, which may beformed from polymerisation of one or more, typically two or three,monomers, which may be present in differing amounts. Preferably the oneof the monomers is a substituted alkyl methacrylate or acrylate monomer.The alkyl group of the substituted alkyl function may have from 1 to 10,preferably 1 to 4 carbon atoms and the substituent group may be analkoxy group with 1 to 4 carbon atoms, such as a methoxy group, or adialkylamino group, such as dimethylamino. Particularly preferredacrylate monomers are: 2-methoxyacrylate (MEA), 3,5,5-trimethylhexylacrylate (TMHA), ethylene glycol acrylate (EGA), 2-ethoxyethyl acrylate(EOEA), ethylene glycol diacrylate (EGDA), ethyl 2-ethylacrylate (EEA),(ethyl-cyano)acrylate (ECA), ethyl 2-propyl acrylate (EPA), ethyl2-(trimethylsilylmethyl)acrylate (ETMSMA), butyl acrylate (BA),butylcyclohexyl acrylate (BCHA), benzyl 2-propyl acrylate (BPA),carboxyethyl acrylate (CEA), 2-(diethylamino)ethyl acrylate (DEAEA),2-(diethylamino)propyl acrylate (DEAPA). The examples of preferredmetharcylate monomers are: methylmethacrylate (MMA), 2-hydroxyethylmethacrylate (HEMA), 2-methoxymethacrylate (MEMA), 2-(diethylamino)ethyl methacrylate (DEAEMA), 2-aminoethyl methacrylate (AEMA), benzylmethacrylate (BMA), 2-butoxyethyl methacrylate (BEMA),2-(tert-butylamino)ethyl methacrylate (TBAEMA), cyclohexyl methacrylate(CHMA), ethylene glycol methacrylate (EGMA), 2-(diisopropylamino)ethylmethacrylate (DIPAEMA). Preferred acrylamide/methacrylamide monomersare: alkylacrylamide (AAAm), butylacrylamide (BAAm), diethylacrylamide(DEAAm), N,N-dimethyl acrylamide (DMAAm), ethylacrylamide (EAAm),hydroxyethyl acrylamide (HEAAm), hydroxymethyl acrylamide (HMAAm),N-isopropyl acrylamide (NIPAAm), N,N-diethylmethacrylamide (DEMAAm),N-diphenyl methacrylamide (DPMAAm). Preferred polymers comprise two ormore monomers and typically a mixture of MEMA or MEA, and DEAEMA, in aweight ratio of 30:70 to 80:20. Preferred ratios of MEMA or MEA toDEAEMA are 70:30 and more preferably 55:45 or 50:50. Optionally furthermonomers may be present, such as acrylic acid (AA) or methacrylic acid(MAA) in a weight ratio of 1 to 10 percent, preferably about 5 percentby weight. A suitable polymer includes MEMA, DEAEMA and AA in a ratio of55:40:5 to 75:20:5. Such polymers may comprise one or more monomerswhich include an aryl group, such as styrene (St) and optionally adialkylacrylamide group (alkyl representing 1 to 4 carbon atoms), suchas dimethylacrylamide (DMAA); and diethylacrylamide (DEAA). Preferablythe polymers comprise two monomers selected from styrene and adialkylacrylamide. Preferred polymers comprise, or consist of thefollowing monomers: St:DMAA and St:DEAA and which may be present in thefollowing ratios 40:60 to 95:5, such as 50:50 to 90:10, for example50:50, 70:30 or 90:10. Additional polymers which may be used in binderformulations may comprise MEA (2-methoxyacrylate) and adialkylacrylamide group (alkyl representing 1 to 4 carbon atoms), suchas dimethylacrylamide (DMAA); and diethylacrylamide (DEAA). Preferredpolymers comprise or consist of MEA:DMAA and MEA:DEAA, which may bepresent in the following ratios 30-80:70-20% respectively, such as50-70:50-30%. Particularly preferred polymers are MEA (45%):DEAA (55%)and MEA (65%):DMAA (35%).

According to another embodiment of the invention, the binder compositionmay comprise a polyurethane matrix polymer which provides bond strengthand faster curing. Polyurethane polymers may be formed by polymerising apolydiol with a di-isocyanate and optionally with an extender molecule,such as a diol. The extender molecules have the effect of modifying thephysical character of the polymers, for example, polymer shape,viscosity and polymer state. The polydiol may be selected from the groupconsisting of but not limited to, poly(polypropyleneglycol)-poly(ethylene glycol) (PPG-PEG), polyethylene glycol (PEG),poly(caprolactone)-diol (PCL-diol), poly(lactic acid)-diol (PLA-diol),poly(glycolic acid)-diol (PGA-diol), poly(tetramethylene glycol) (PTMG)also known as poly(butylene glycol), poly[1,6-hexanediol/neopentylglycol-alt-(adipic acid)]diol (PHNAD), poly[1,6-hexanediol/neopentylglycol/diethylene glycol-alt-(adipic acid)]diol (PHNDGAD), poly(dimethylsiloxane)-diol (PDMS). The molecular weight of the polydiol may rangefrom M_(n)=200 to M_(n)=7000 and it may be present in an amount of15-55% by weight, such as 20-50% by weight of the polymer. Thedi-isocyanate may be selected from the group consisting of but notlimited to methylene diphenyl diisocyanate (MDI), 1,4-phenylenediisocyanate (PDI), 1,1′-methylenebis(4-isocyanatocyclohexane) (HMDI),2,4-toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI),1,3-bis(isocynanatomethyl) cyclohexane (BICH). Typically thedi-isocyanate is present in an amount of 45-55% by weight of thepolymer. Suitable extenders include 1,4-butanediol (BD), ethylene glycol(EG), 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol (OFHD); and3-dimethylamino-1,2-propanediol (DMAPD). When present, the extender maybe present in an amount of 10-30 mol % of the polymer, typically 10-25%.

In yet another embodiment, the binder composition may comprisepolyesters, copolymers or mixtures (blend) thereof. Non limitingexamples of preferred polyesters are: polyglycolide or polyglycolic acid(PGA), polylactic acid (PLA), polycaprolactone (PCL),polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethyleneadipate (PEA), polybutylene succinate (PBS),poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polyethyleneterephthalate (PET), polybutylene terephthalate (PBT), polytrimethyleneterephthalate (PTT), polyethylene naphthalate (PEN), vectran, and/ortheir copolymers such as PCL-PLA, PCL-PGA, PLA-PGA, etc.

Furthermore, the binder composition of the invention may comprise vinylpolymers. Preferably, these may include polyethylene, polypropylene,polybutadiene, polyvinyl chloride (PVC), polyvinyl acetate (PVAc),polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyvinyl butyral(PVB), and polyvinyl toluene (PVT). The above said polymers may beincorporated into the binder formulation in homogeneous (aqueoussolution) or heterogeneous (emulsion) systems. The solution or emulsionpolymers may be present in the composition in an amount ranging from0.5% up to 50% by weight based on total solids.

In an alternative embodiment, the binder composition of the inventionmay comprise a compound containing one or more azetidinium groups. Suchmaterial is known per se and may be obtained by the reaction of anamino-functional substrate with epichlorohydrin. The azetidinium groupsmay be a part of a polymer chain comprising one or more non-azetidiniummonomer units incorporated into the polymer structure.

The said polymers, more specifically the polymers exemplified above, mayshow a molecular weight ranging from 500 Daltons (Da) to 2×10⁶ Da,preferably from 1×10³-5×10⁵ Da, more preferably 5×10⁴ Da−3×10⁵ Da.

One or more pre-formed polymers, or monomers, possibly together withinitiator, may be emulsion dispersed or solubilised in the bindercomposition.

It has been shown that such binder compositions produce cured bindersshowing high bond strength and performance with fast curing rate underusual curing conditions, notably temperatures ranging from 60-280° C.,advantageously higher than 80° C., preferably higher than 100° C., andadvantageously lower than 250° C., preferably lower than 200° C.,preferably 120-180° C. The duration of applying energy for curingpurposes is not particularly restricted and may vary from 1 to 240minutes, preferably less than 200 min, more preferably less than 120 minor even 60 min. Curing durations of up to 40 min, 30 min or 20 min arepossible.

In such invention compositions, the polyphenolic macromolecular compoundmay make from 60 up to 96% by weight based on the total of the threecomponents; the polyamine functional compound may make from 2 up to 20 w% based on the total of the three components; and the matrix polymercontent may range from 2 to 20 w % based upon the total of the threecomponents. By way of example, compositions of ammonium or sodiumlignosulfonate, HM DA and PVA or sodium carboxymethyl cellulose orhydroxypropyl cellulose advantageously show a weight ratio of 70/15/15.

Another advantage of the curable binder compositions of the invention isthat they produce substantially no or only little water upon curing.This is of particular interest as the energy required for manufacturingof a product containing such cured binder may be significantly reducedas energy for evaporation of the water generated during curing isreduced or no longer required. The reduced water generation duringcuring has a positive impact on the final product with respect to bondstrength and swelling properties.

As a result of the above, the binder composition is particularlysuitable for use in the production of fiber boards, wood boards,particle boards and similar.

According to an alternative embodiment, the polyamine functionalcompound comprises chitosan. Chitosan is a linear polysaccharidecomposed of glucosamine units and bears primary and/or secondary aminefunctional groups. It is a renewable and/or sustainable class ofcompounds that may be derived from crustacean shells and shrimps. It hasbeen used in agriculture, notably in seed treatment. Chitosan may showweight average molecular weights ranging from 500 to 2×10⁶ Daltons.

The ratio between polyphenolic macromolecular compound and chitosanadvantageously ranges from 98:2 to 80:20 w %, preferably from 95:5 to85:15 w % or even to 90:10 w %

In the case of this alternative binder composition, curing mayadvantageously be effected in aqueous solution, preferably at ambienttemperature (notably in the range 10° C. to 25° C.) or slightly elevatedtemperature. Temperatures below 150° C., 130° C. or even below 100° C.,such as at about 80° C. are preferred. Catalysts or surface activeagents are not required but may be added in some particularapplications. Preferably the pH is maintained at or above 8, preferablyat about pH=8.5. Such preferred binder compositions cure with only fewor substantially no water formation, which makes them a binder of choicein the production of mineral wool based insulation products andcellulose based boards, such as wood fiber boards or wood particleboards. The energy required for the manufacturing of such products isparticularly reduced as curing occurs at low temperature and further assubstantially no additional energy is required for water evaporation ordrying of the product. The reduced water generation during curingpositively affects at least the swelling properties of the product madewith the relevant binder composition.

The binder compositions of the invention and binders produced therefromare essentially formaldehyde-free (that is comprising less than about 1ppm formaldehyde based on the weight of the composition) and do notliberate substantial formaldehyde. They are preferablyformaldehyde-free. Furthermore they are preferably based on natural,hence renewable, resources.

The compositions may further comprise dyes, antifungal agents,antibacterial agents, dedusting oil, hydrophobic agents and otheradditives, or mixtures thereof, for example in amounts ranging from 0.1to 15% by weight of binder solids. Silicon-containing coupling agentsmay be present in such binder, generally in the range from about 0.1 toabout 5% by weight based on the weight of the solids in the bindercomposition. Dedusting oil may be present at up to 10 wt. %.

Without being bound by theory, it is believed that curing generateshighly crosslinked high molecular weight polymers. These may be analysedby a sol-gel method, rheology and other known techniques.

The preferred binders generated by curing the aqueous bindercompositions of the invention are environmentally friendly as they arebased on natural products and essentially free of formaldehyde. Inaddition, in some embodiments, curing may be effected under reducedtemperatures as compared to known binder compositions, which alsofavourably adds to the environmental related aspects of the binders.

According to the present invention, the term “binder composition”includes any composition comprising a polyphenolic macromolecularcompound and a polyamine functional compound which is capable of bindingloosely assembled matter, either as such or upon curing.

As used herein, the term “aqueous” means a solution and/or dispersionwhich comprises water as a solvent. Said term further includescompositions or mixtures which contain water and one or more additionalsolvents. An “aqueous binder composition” of the invention may be asolution or partial solution of one or more of said binder components ormay be a dispersion, such as an emulsion or suspension.

The solid content of the aqueous binder composition may range from 2 to95 w %, advantageously from 8 to 90 w %, preferably from 10 to 85 w %,based on the weight of the total aqueous binder composition. Morespecifically, when used as a binder for mineral wool insulation, thesolid content of the aqueous binder composition may be in the range from2 to 25 w %, preferably from 8 to 20 w %, more preferably from 10 to 20w % or even 12 to 18 w %, based on the weight of the total aqueousbinder composition. When used as a binder in wood boards, the solidcontent of the aqueous binder composition may range from 50 to 95 w %,preferably 50 to 90 w %, more preferably 55 to 85 w % or even 60 to 80 w%, based upon the weight of the total aqueous binder composition.

The components of the binder composition may be transported separatelyand combined shortly before use in the relevant manufacturing plant. Itis also possible to transport the binder composition as such.

The binders of the invention may be used to bond a collection of non orloosely assembled matter. The collection of matter includes anycollection of matter which comprises fibers selected from mineralfibers, slag wool fibers, stone wool fibers, glass fibers, aramidfibers, ceramic fibers, metal fibers, carbon fibers, polyimide fibers,polyester fibers, rayon fibers, and cellulosic fibers. Further examplesof collection of matter include particulates such as coal, sand,cellulosic fibers, wood shavings, saw dust, wood pulp, ground wood, woodchips, wood strands, wood layers, other natural fibers, such as jute,flax, hemp, straw, wood veneers, facings and other particles, woven ornon-woven materials. According to a specific embodiment of theinvention, the collection of matter is selected from wood particles andmineral fibers.

In one illustrative embodiment, the binder composition of the inventionmay be used to make thermal insulation products, comprising mineralfibers. In such an application, the fibers are bonded together such thatthey become organized in a fiberglass mat which may then be processedinto an insulation product. In such an application, the fibers aregenerally present in an amount ranging from 70 to 99% by total weight ofthe insulation product, notably from 80 to 99% or from 85 to 99%.

According to another embodiment of the invention, the binder may be usedto bond cellulosic particles, such as cellulosic fibers, wood shavings,wood pulp and other materials commonly used to manufacture compositewood boards, including fiber boards, particle boards, oriented strandboards, plywood etc. Such wood boards show nominal thicknesses rangingfrom 6 to 30 mm and a modulus of Elasticity of at least about 1000N/mm2, bending strength of at least about 5 N/mm2 and/or an internalbond strength of at least 0.10 N/mm2. In such applications, the bindercontent in the final wood board may range from about 5 to 30% wt withrespect to the total weight of the wood board notably from 9 to 20%. Themain components of the aqueous uncured binder composition, that is thepolyphenolic macromolecular compound and the polyamine functionalcompound may be at least partially soluble in water.

The aqueous binder composition may be applied onto the fiber orparticular material by spray application. Other possible techniquesinclude roll application or mixing and/or tumbling the collection ofmatter with the binder composition. As water evaporates the bindercomposition may form a gel that bonds the particulate material togetherwhen arranged into a desirable assembly. When curing, the polyphenolicmacromolecular compound and the polyamine functional compound are causedto react to form an essentially water insoluble macromolecular binder.Curing thus imparts increased adhesion, durability and water resistanceas compared to uncured binder. Curing may be effected at temperaturesbetween ambient and up to 280° C.

According to another aspect, the invention covers a process for thepreparation of an assembly of fibrous materials or particulate materialswherein a combination of (i) an aqueous composition of a polyphenolicmacromolecular compound which bears a multitude of phenol orpolyhydroxybenzene radicals, such as catechol radicals(dihydroxybenzene), preferably lignosulfonate salts and condensedtannins and mixtures thereof, and (ii) an aqueous composition of apolyamine functional compound comprising primary and/or secondary and/ortertiary and/or quaternary amine functional groups is appliedsequentially or simultaneously onto a collection of fibers or particlessuch that the ratio of polyphenolic macromolecular compound to polyaminefunctional compound ranges from 98:2 to 70:30 w %, preferably from 95:5to 80:20 w %, or an aqueous binder composition as defined above isapplied onto a collection of fibers or particles, the coated fibers orparticles are gathered in an assembly and subjected to curing conditionswhereby the polyphenolic macromolecular compound and the polyaminefunctional compound are caused to react to form a macromolecular binderand water is evaporated. The obtained product may then be furtherprocessed in suitable process steps to make intermediate or finalproducts, including but not limited to insulation products or woodboards.

A further polymer may be concomitantly or successively applied onto thecollection of fibers or particles, and curing may be performed at atemperature ranging from 100° C.-200° C., preferably higher than 140°C., more preferably lower than 190° C., typically between 160 and 180°C.

As mentioned the polyamine functional compound may be selected fromdiamines, triamines, tetramines, pentamines and polymeric plolyamines orpolyimines. Examples are hexamethylenediamine, diethylenetetramine,diethylenetriamine, polyethyleneimine (PEI), polyvinyl amine, polyetheramine, polylysine, ethylene diamine, 1,3-diaminopropane, cadaverine,spermidine, spermine, putrescine, tetraethylmethylenediamine, andtriethylenetetramine. As is known to the skilled person, severaldifferent types of polyethylenimines are available, such as linearpolyethylenimines, branched polyethylenimines and dendrimer typepolyethylenimine. Similarly, polyetheramines may show a linear form andbranched forms, and all are believed to be suitable for the generationof binder compositions and, hence, binders of the invention.

The ratio of polyphenolic macromolecular compound to polyaminefunctional compound ranges from 98:2 to 70:30 w %, preferably from 95:5to 80:20 w %.

Preferably, the ratio of reactive groups on the macromelules to reactiveamino groups in the amine components may be in the range of 10:1 to 1:1.

Preferred binder compositions comprise a lignosulfonate salt, preferablyammonium lignosulfonate or calcium or magnesium lignosulfonate, and adiamine, such as hexamethylenediamine (HMDA).

When the polyamine functional compound is selected from chitosan showingweight average molecular weights ranging from 500 to 2×10⁶ Daltons,curing may be performed at a temperature ranging from ambient to 180°C., preferably less than 160° C., more preferably less than 140° C.,even more preferably less than 120° C. or 100° C., under oxidizing andalkaline conditions.

The invention will be explained in more details in the examples belowwith reference to the attached Figures, in which:

FIG. 1 shows the cure rate at 160° C. for variousammonium-lignosulfonate compositions;

FIG. 2-4 show the cure rate at 180° C., 160° C. and 140° C.,respectively, of various binder compositions;

FIG. 5-10 show the mechanical strength of several binder compositions;

FIG. 11-12 give an indication of weathering stability by comparison ofautoclaved and non-autoclaved composite binder compositions.

EXAMPLE 1: PREPARATION OF BINDER COMPOSITIONS COMPRISINGLIGNOSULFONATES, POLYAMINES AND POLYMER

Calcium lignosulfonate (Borrement CA 2120) was provided by BorregaardLignoTech. Sodium lignosulfonate was purchased from Aldrich, andammonium lignosulfonate was obtained from TemBac.

Sodium carboxymethylcellulose (NaCMC), hydroxypropylcellulose (HPC) andhydroxyethylcellulose (HEC) were obtained from Aldrich and showed a Mwof approx. 250 kDa, 100 kDa and 100 kDa, respectively.

The amine functional material such as hexamethylene diamine (HMDA) anddiethylenetriamine (DETA) were obtained from Aldrich. Different types ofpolyethylenimines (Lupasol® EO, Lupasol® PS, Lupasol® P and Lupasol®G100), polyvinyl amines (Luredur® VM, Luredur® VH and Luredur® VI), wereobtained from BASF Chemical Company, and polyetheramines(JeffamineED600, JeffamineEDR148, JeffamineT403) from Huntsman HollandBV.

The required amounts of polymer and lignosulfonate (LS) were dissolvedin water individually. The required amount of polyamine functionalcompound was added to the LS solution followed by homogenization. Thepolymer solution and LS-amine solution were then combined at ambienttemperature and stirred at 500 rpm for 30 minutes.

EXAMPLE 2: BINDER WEIGHT LOSS DETERMINATION

The 2-5% (solids content) binder solutions were prepared as describedabove and poured into a petri dish. Weight was determined. The Petridish was then kept for 2 hours in an oven at 140° C. and weighted again.Weight loss was determined; results are shown in the Table below.

TABLE 1 Evaluation of binder weight loss, at 140° C. for 2 hours. BinderWeight Formulations Loss (%) 70% Am LS + 15% HMDA + 15% PVA 1.765 70% AmLS + 15% HMDA + 15% HPC 2.40 70% Am LS + 15% HMDA + 15% Na CMC 2.60 70%Ca LS + 15% HMDA + 15% PVA 4.54 70% Ca LS + 15% HMDA + 15% HPC 6.533 70%Ca LS + 15% HMDA + 15% Na CMC 8.517

EXAMPLE 3: CURE RATE STUDY

A 50 μl fraction of the binder solution was applied onto a spot of glassmicrofiber filter (Whatman™) surface. Samples were cured from 1 min upto 20 minutes at different temperatures in an appropriate oven. Aftercuring, each glass filter sample was cut and fully immersed in 50 mlcold water contained in a 150 ml glass beaker, and sonicated for 15 minat room temperature. The extract solution filtered and the absorbance ofthe extract was measured with a spectrometer at 470 nm. The absorbancewas then plotted as a function of cure time.

The cure rate at 160° C. was determined for various compositionscomprising ammonium-LS and HMDA (10-20 w %). Results are shown in FIG.1.

The test was repeated at three different cure temperatures (140° C.,160° C. and 180° C.) for various binder compositions of the invention.Results are shown in FIGS. 2-4. It appears from the results that thethree way compositions show a faster curing.

EXAMPLE 4: BOND STRENGTH ANALYSIS

In order to determine the bond strength of binders, initiallyimpregnated glass veils (non-woven glass fibers) of A4 size were placedinto a muffle furnace for 30 minutes at 600° C. in order to ensureburnout of impregnation material and thereafter cooled for 30 min.Approx. 400 g of the prepared binder solutions were poured into separatedip trays and the burnout veils were carefully totally immersed into therelevant binder solutions. The thus impregnated veils were then cured atdesired temperatures (e.g. 180° C.) and during relevant periods of time(up to 20 minutes).

The bond strength analysis was performed using a testometric machine(M350-10CT) of the binder impregnated cured veils. For each test a curedbinder impregnated A4 veil was cut into 8 equal strips. Each strip wastested separately using a 50 Kg load cell (DBBMTCL-50 kg) with a testspeed of 10 mm/min, controlled by winTest Analysis software. Glass veiltensile plates were attached to the testometric machine to ensure a 100mm gap between plates. The samples were placed vertically in thegrippers, within the rubber grip area, and the force tared to zero.Further, onscreen instructions were followed, and generated datareported as herein below. Various parameters such as maximum load atpeak, stress at peak and modulus at peak were evaluated by the software,and data presented as an average for 8 samples with standard deviation.The average maximum load at peak/stress at peak is considered as thebond strength.

The mechanical strengths, force at peak, is presented in FIG. 5 forammonium-lignosulfonate (AmLS) per se, AmLS/HMDA/HPC (70/15/15),AmLS/HMDA/CMC (70/15/15), AmLS/HMDA/PVA (70/15/15), AmLS/HMDA/HPC(65/15/20) and AmLS/HMDA/HPC (65/15/20) with 2% HDI (hexamethylenediisocyanate oligomer).

The mechanical strengths, force at peak is presented in FIG. 6 forcalcium-lignosulfonate (CaLS) per se, CaLS/HMDA/HPC (70/15/15),CaLS/HMDA/CMC (70/15/15), CaLS/HMDA/PVA (70/15/15) and CaLS/HMDA/HEC(70/15/15).

Corresponding data is shown in FIG. 7 for Na-lignosulfonate (NaLS) perse, NaLS/HMDA/HPC (70/15/15) and NaLS/HMDA/CMC (70/15/15); and in FIG. 8for Magnesium-lignosulfonate (MgLS) per se and MgLS/HMDA/NaCMC(70/15/15).

Further data has been generated with CaLS, various polyamines selectedfrom diethylenetriamine, polyethylenimine and polyvinylamine (PVAm), andpolymers, more specifically CaLS/DETA/NaCMC (70/15/15), CaLS/DETA/PVA(70/15/15), CaLS/PEI-EO/NaCMC (70/15/15), CaLS/PEI-EO/PVA (70/15/15) andCaLS/PVAm/PVA (70/15/15)—see FIG. 9.

FIG. 10 shows further force at peak data generated forAmLS/JeffamineED600/NaCMC (70/15/15), AmLS/JeffamineEDR148/NaCMC(70/15/15), AmLS/JeffamineT403/NaCMC (70/15/15), AmLS/PLL/NaCMC(70/15/15) and AmLS/PLL/PVA (70/15/15).

EXAMPLE 5: WEATHERING STABILITY

Dry and weathered tensile strength provide an indication of thedurability of a glass fiber mat. Binder impregnated cured veils(non-woven glass fibers) were placed in an autoclave (J8341, Vessel:PVO2626). The samples were subjected to 90% humidity atmosphere, in atemperature range of from 40° C. to 110° C. (full cycle), under apressure of up to 2.62 bar for 3 hours. The samples were subsequentlydried completely such that no moisture remains on the veil samples.These autoclave treated samples were tested using testometric machine(M350-10CT) for bond strength analysis (see example 4 above), and theresults were compared with those from samples that have not beensubjected to the humidity treatment (autoclave).

FIG. 11 compares force at peak data for AmLS/HMDA/HPC (65/15/20) beforeand after sterilization and AmLS/HMDA/HPC (65/15/20)+HDI (2%) before andafter autoclave.

FIG. 12 compares force at peak data for CaLS/HMDA/HPC (70/15/15) beforeand after sterilization, CaLS/HMDA/NaCMC (70/15/15) before and afterautoclave and compares force at peak data for AmLS/HMDA/HPC (65/15/20)before and after autoclave and CaLS/HMDA/PVA (70/15/15) before and afterautoclave.

No significant loss of mechanical strength has been noticed. Somesamples even show increased mechanical strength after autoclaveweathering.

Interestingly, the polymerization reaction generates little or no water,thus reducing the energy required for production of the final insulationproduct.

EXAMPLE 6: PREPARATION OF A COMPOSITE WOOD BOARD

Wood in the form of assorted pine wood shavings was purchased and usedas received. The wood was placed in a plastic container and a bindersolution prepared in accordance with Example 6, at 80 w % solids(determined as bake out solids after drying at 140° C. for 2 hours), wassprayed onto the wood sample, during which the wood was gently tumbledin order to become uniformly coated. Samples of resinated wood wereplaced in a collapsible frame and compressed between heatable plates atapprox. 2000 kPa, during 25 to 30 minutes, and maintained at about 80°C. The obtained board sample was well-bonded internally, smoothsurfaced, mechanically strong and relatively water-resistant in theabsence of any hydrophobic or other additive other than the main bindercomponents. Estimated binder content: approx. 13 w %.

1. An aqueous curable binder composition comprising (i) a polyphenolicmacromolecular compound which bears a multitude of phenol orpolyhydroxybenzene radicals, such as catechol radicals(dihydroxybenzene), preferably lignosulfonate salts and condensedtannins and mixtures thereof, and (ii) a polyamine functional compoundcomprising primary and/or secondary and/or tertiary and/or quaternaryamine functional groups, and/or reaction product of (i) and (ii), theratio of polyphenolic macromolecular compound to polyamine functionalcompound ranging from 98:2 to 50:50, preferably from 98:2 to 70:30 w %,more preferably from 95:5 to 80:20 w %.
 2. The aqueous curable bindercomposition of claim 1 wherein the lignosulfonate salt is selected fromcalcium lignosulfonate, sodium lignosulfonate, ammonium lignosulfonate,magnesium lignosulfonate and mixtures thereof.
 3. The aqueous curablebinder composition of claim 1 wherein the polyamine functional compoundis selected from diamines, triamines, tetramines, pentamines andpolymeric polyamines or polyimines, such as hexamethylenediamine,diethylenetetramine, diethylenetriamine, polyethyleneimine (PEI),polyvinyl amine, polyether amine, polylysine, ethylene diamine,1,3-diaminopropane, cadaverine, spermidine, spermine, putrescine,tetraethylmethylenediamine, and triethylenetetramine, different types ofpolyethylenimines, such as linear polyethylenimines, branchedpolyethylenimines and dendrimer type polyethylenimine, andpolyetheramines in linear and branched form.
 4. The aqueous curablebinder composition of claim 2 comprising a lignosulfonate salt,preferably ammonium lignosulfonate or calcium lignosulfonate ormagnesium, and a diamine, such as hexamethylenediamine (HMDA).
 5. Theaqueous curable binder composition of claim 1 further comprising amatrix polymer selected from naturally derived polymers, such aspolysaccharides, such as cellulose, starch, alginate, hyaluronic acid,and their derivatives, carboxymethyl cellulose (CMC), sodiumcarboxymethyl cellulose (NaCMC), hydroxypropyl cellulose (HPC),2-hydroxyethyl cellulose (HEC), oligosaccharides, synthetically derivedpolymers, such as polyvinyls (PVA, PVAc, PAN), polyacrylics,polyacrylate, polymethacrylate, polyacrylamide, polymethacrylamides,polyurethanes, polyesters, aliphatic isocyanate oligomers, azetidiniumcontaining polymer, chitosan and its derivatives, copolymers thereof andmixtures thereof.
 6. The aqueous curable binder composition of claim 5wherein the polyphenolic macromolecular compound makes from 50 up to 98w % based on the total of the three components; the polyamine functionalcompound makes from 1 up to 40 w % based on the total of the threecomponents; and the polymer content ranges from 1 to 20 w % based uponthe total of the three components.
 7. The aqueous curable bindercomposition of claim 1 further comprising dyes, antifungal agents,antibacterial agents, hydrophobes, silicone containing coupling agentsand/or other additives such as silane, dedust oil, hydrophobic polymers,and/or combinations thereof.
 8. An assembly of fibers or particlesbonded with an aqueous binder composition according to claim 1 or with abinder resulting from the curing of a binder composition according toclaim
 1. 9. The assembly of fibers according to claim 8 being aninsulation product, such as a mineral wool mat.
 10. The assembly ofparticles according to claim 8 being a composite wood board, such as awood fiber board, wood particle board, plywood or similar board.
 11. Aprocess for the manufacturing an assembly of fibers or particlescharacterized in that a combination of (i) an aqueous composition of apolyphenolic macromolecular compound which bears a multitude of phenolor polyhydroxybenzene radicals, such as catechol radicals(dihydroxybenzene), preferably lignosulfonate salts and condensedtannins and mixtures thereof, and (ii) an aqueous composition of apolyamine functional compound comprising primary and/or secondary and/ortertiary and/or quaternary amine functional groups, is appliedsequentially or simultaneously onto a collection of fibers or particlessuch that the ratio of polyphenolic macromolecular compound to polyaminefunctional compound ranges from 98:2 to 50:50, preferably 98:2 to 70:30w %, more preferably from 95:5 to 80:20 w %, or an aqueous bindercomposition according to claim 1 is applied onto a collection of fibersor particles, in that the coated fibers or particles are gathered in anassembly and subjected to curing conditions whereby the polyphenolicmacromolecular compound and the polyamine functional compound are causedto react to form a macromolecular binder and water is evaporated. 12.The process according to claim 11 wherein the polyamine functionalcompound is selected from diamines, triamines, tetramines, pentaminesand polymeric plolyamines or polyimines, such as hexamethylenediamine,diethylenetetramine, diethylenetriamine, polyethyleneimine (PEI),polyvinyl amine, polyether amine, polylysine, ethylene diamine,1,3-diaminopropane, cadaverine, spermidine, spermine, putrescine,tetraethylmethylenediamine, and triethylenetetramine, different types ofpolyethylenimines, such as linear polyethylenimines, branchedpolyethylenimines and dendrimer type polyethylenimine, andpolyetheramines in linear and branched form.
 13. The process accordingto claim 11 characterized in that curing is performed at a temperatureranging from 90° C.-200° C., preferably higher than 140° C., morepreferably lower than 190° C., typically between 160 and 180° C.
 14. Theprocess of claim 11 wherein the aqueous binder composition is applied byspraying onto the collection of fibers or particles.
 15. The process ofclaim 11 wherein the assembly is a wood fiber board or wood particleboard or similar wood board, subjected to pressing during curing.